Conduit forming machine with dowel pin hole former



Oct. 8, 1963 J. c. MCGREW CONDUIT FORMNG MACHINE WITH DowEL PIN HOLEFORMER Filed Nov. 5, 1958 2 lSheets-Sheet 2 dame: C Mc Grew INVENTOR.

United States Patent 3,106,005 CNDUIT FORMING MACHINE WITH DOWEL PINHOLE FURMER James C. McGrew, Bellaire, Tex., assigner of small intereststo various assignees Filed Nov. 5, 1958, Ser. No. 772,031 2 Claims. (Cl.25-36) This invention relates to machines for manufacturing multiholeconduits such as the conduit utilized in laying undergroundcommunie-ation cable or the like.

The present general practice in laying underground cable forcommunication lines is to run cables through buried conduit. Multieellor multiduct conduit is utilized. The conduit employed most widely in.the past has been a tired clay. This product requires a clay `of veryparticular qualities and is available in limited quantities. Untilrecently there has not been 'an adequate alternative to this product.Recently a machine has been pnovided for manufacturing multihole conduitfrom concrete or the like which may be utilized in running cable and forother purposes for which conduit may be used. In that machine aplurality of packer heads is employed corresponding in number to thenumber of ducts to be formed in the multiduct conduit desired, each ofthese heads being somewhat similar to the single packer head previouslyused in fabricating single bore concrete conduit. In such a machine therotating packer heads in eiiect provide the packing Walls for eachother; -that is, one packer head in rotating packs against an .adjacentpacker head, land it is not necessary to have a Wall of the moldVsurrounding each packer head. These packer heads are caused to travelendwise through a mold as the mold is filled with cement mix and causethe packing of the mix around the packer heads which in passing throughthe mold leave the desired ducts through the formed concnete behindthem.

To provide means for aligning adjacent sections of conduit small dowelpin holes are formed in each end of each section of conduit. Such holesare useful in single duct conduit but .the necessity for them isparamount in multiduct conduit. In previous machines the means forforming these dowel pin holes has involved dowel pin hole forming pinsmounted on the end walls of the forms. Then when or `after the end walls`are removed from the formed conduit the hole for-ming pins are removed`and the holes yare left for the reception of dowel pins.

This arrangement usually resulted in the formation of satisfactory dowelholes, especially when the pins were removed after the concrete had set,but the operation of removing the [dowel hole forming pinsV was thenquite difficult, requiring painstaking effort, and frequently resultingin damage to the conduit section which required either repair work yor`discard of the conduit section. The darnage to the conduit was evenmore apt to occur if the removal Was before setting.

It is, therefore, an object of this invention to provide a concreteconduit forming machine with dowel hole forming mechanism which willavoid the difficulties experienced with prior arrangements. l

Another object is to provide for removal of dowel hole forming meansfrom a concrete conduit before it sets but without damage to theconduit.

Another object of this invention is to provide such a dowel hole formingmechanism which will be automatically retracted and withdrawn from theformed conduit and the form therefor at the end of the formingoperation, without opportunity for damage to the formed section andwithout the requirement of any arduous effort for the removal of suchhole forming means. v

`Other objects and advantages of this invention will become apparentfrom the following description taken in connection with the accompanyingdrawings wherein is set forth by w-ay of illustration and example `oneembodiment of this invention.

In the drawings:

FIG. 1 is a view partly in front elevation and partly in longitudinalcross-section illustrating a machine-constructed in accordance with thisinvention, with the various parts in the position they occupy at the endof a forming operation.

FIG. 2 is a perspective of a multiduct conduit section having dowelpinholes formed Yin its end after the manner in which such holes areadapted to be formed by the present invention, iandillustrating a dowelpin of the type adapted to be used in such holes.

FIG. 3`is a view partly in side elevation and partly in longitudinalcross-section illustrating the Same machine as shown in FIG. 1. v

FIG.- 4' is afragmentary view partly in front elevation and partly inlongitudinal cross-section'illustrating the samemachine as shown inFIGS.v l -iand 3 but with the parts, including the idowel hole formingmechanism, in the positions which they occupy during the forming of thesection of conduit.

FIG. 5 is an enlargedfragmentary view illustrating in more ydetail thedetent for the dowel hole forming pins shown in FIG. 3, parts beingbroken aw-ay for clarity.

The objects of this invention are accomplished by the provision of meansfor forming the dowel pin holes, comprising pins that extend throughopenings in the end walls of the form instead of being secured to theend walls, and which are .adapted Vto be Withdrawn While the end wallsare still -in place so that there is no tendency to pull away a portionof the formed conduit section in the extraction of the hole formingmeans. The present invenion also Y i. provides a mechanism forming partof a machine in which such multiduct conduit is made which mechanismwill cause the entrance of the dowel pin hole forming means into ltheform to the proper ldegree when ythe form is in place yand as the packerheads which pack the slurry in the form and for-m the ducts therethroughare moved into position to begin the forming of a section of conduit.Mechanism is `also provided :whereby when the conduit section iscompletely formed a slight additional movement of the packer heads toremove them from the forms causes also the extraction of the-dowel p-inhole forming mechanism from the'forms before the vend Walls of theforms` are removed. Referring more in detail to the drawings, theinvention 1s illustrated in connection with a multiduct conduit formingmachine which isgenerally carried by a suitable frame- Y Work consistingofupright members 1 and 2 mounted on a suitable foundation 3 and havingsuitably located cross members 4 and 5 and a transverse support 6 whichVin the illustration is shown as interrupted adjacent the central portionthereof so as to permit passage of -the duct forming packerheads andtheir yassociated equipment,

as Nvell as of that portion of the dowel pin hole forming mechanismwhich forms the dowel pin holes inthe upper end of the concrete conduitsection.

` In the type of machine illustrated a movable form support 7 isprovided for supporting the form 8 in upright position for the formingoperation. This platformor suppor-t is preferably made movable tofacilitate the removal of the form after the forming operation iscomplete and in the present instance is illustrated las being in theform 'of a turntable mounted yon ia central pivot9 as shownv in FIG. 3.

The form 8 is provided with a bottom Wall 10' removably securedtherein.k This bottom wall 10 is provided with openings which are of adiameter substan- Patentecl Oct.V 8, v1963 y 1 3 Y tially the diameterof the ducts to be formed in the iinished conduit section. The purposeof these openings will presently appear.

The bottom wall of the form is also provided with openings 12 of a sizeand in positions corresponding to the positions in which it is desiredthat dowel pin holes be formed in the lower end of thel nished conduit.These positions are the same as the positions at which dowel hole pinforming pins were secured in previous machines to the bottom wall of theform and their utility in accordance with the present invention willpresently appear. The support table 7 has an opening 11 approximatelythe size of and registering with the bottom wall. of the form.

The frame is provided with a guide in the form of upright bars 13secured at their opposite ends by nuts or the like 14 to the crossmember d at their upper ends and to the Support members 6 at their lowerends. Slida-bly mounted on this guide is a slide 15' in which is carrieda gear box 16 for converting the drive from a driving shaft 17 intorotation of the various packer head carrying and operating shafts 1Swhich extend downwardly from the gear lbox 16. These have on their lowerends packer heads 19 of suitable character the details of which form lnopart of the present invention but which ordinarily have upper packerportions and lower `troweling portions. The driving shaft 17, whilebeing permitted to move upwardly and downwardly, is adapted to berotated by any suitable means such as a motor Ztl, a belt drive 21therefrom to a driving bevel -gear 22 which is in turn in mesh with adriven'bevel gear 23` having splines therein adapted to receive thesplined upper end of the shaft 17.

Suspended fromV the slide 15 by means of suspension rods 24 is a loadingtable 25 which `is mounted between the side frame members 1 and 2l-for'upward and down-` ward sliding movement. A lost motion connectionis provided between this table 2,5 and the slide 15 by making thesuspension rods 24 slidable within the slide 15 v to a degree whiohislimited :by the ynuts 26 engaging these rods on top or the slide 15. Thelower ends of these rods are secured to the table 25 by means of nuts27.

It will beseen that ,as slide 15 starts downwardly the table 25 willmove with it until this table rests upon the top of ythe form 8,whereupon its downward movement will be arrested. However, the slide15u/ith its pendant packer heads 19 may continue its downward movementuntil these packer heads 19 extend not .only through the bottom wall 10of the form S but also through the support table 7 as illustrated inFIG. 4.

When at restv upon the top of the form 8 the table 25 serves as the`=top wall of ythis form and has appropriate openings to permit thepassage therethrough of the packer heads 19, as rwell as smaller pinopenings 23 to permit the passage therethrough of the dowel pin holeforming pins. This table 25 also has an upstanding ange 2.9 on its uppersurface providing a `shallow hopper adapted to receive cement slurry ormix from a conveyor mechanism 30, so that such mix may -be fed throughthe openings lin the table.

Any suitable means may be provided for raising and loweringthe slide 15.The means illustrated is a pair of hydraulic cylinders v31 havingpistons therein actuating piston rods 32, the upper ends of which aresecured to the laterally extending elements 33 on the slide d5.

Heretofore dowel holes 34 for pins 30.151 have in the past been formedin conduits 35 having ducts 36 by means of pins secured to the bottomplate 161 and to the top plate or table 25, in each case -beingwithdrawn when or after `the top or bottom plate is removed, as the oasemay be. Since the form was usually set on its lower end during curing ofthe concrete, the lower end plate and lower pins were not removed untilafter curing.

Directly beneath that portion of the table which carries the form 8 isprovided a pit or other space 37 in which are mounted dowel hole formingmeans movable upwardly -through the holes 12 into the form anddownwardly to a position below the table 7. An exemplary structureincludes suitable guides such as the upright guide posts 38. On theseguide posts 38 is a slide -or cross bar 39 carrying pins 4d' extendingupwardly therefrom and held in alignment with the openings 12 by meansof openings in a cross bar 41 on the 4guide posts 38. The cross head 39may have its weight partially counterbalanced by suitable `springs 42extending upwardly and engaging the ends of the cross bar 41. The crosshead 39 may be moved upwardly until the upper ends of the pins 4rdproject into the interior of the form 8 through the bottom wall 10. Aconduit formed while the pins are thus in place within the form 8 willbe formed with dowel pin holes 43 in its lower end.

The cross head 39 is provided with lugs 44 adjacent its opposite ends,to which are secured duplicate operatingV mechanisms. Each has la rod 45extending upwardly lfrom the lug 44. The upper end of this rod 4,5 ispivotally connected at lo to one end of a lever 417 whose fulcrum is at48. Adjacent the same end of the lever 47 there is pivoted thereto at`49' a second rod 50 which at its upper end is connected to a secondactuating lever 51 at 52. The lever 51 is fulcrumed at 53 and has itsend opposite the pivot 52 disposed to be engaged by the lower portion ofthe slide 15 vas this slide nears the lower extremity of its travel.After the slide 15 engages the lever 511, it will swing the lever 51from the solid line position to the dotted line position shown in FIG.3. This operation will pull upwardly on the rod and on the rod 45,swinging the lever i7 to its dotted line position and moving the lug 44upwardly to its dotted ine, position. This moves the pins 41B upwardlyuntil they project into the form far enough to form the dowel pin holese3 when a conduit is formed in the form 8.

In order to hold the pins 40 in their upper position during the fillingof the form, one or more forked levers 39a are provided, each straddlingthe cross head 39 and mounted on a fixed pivot 3912. A spring 42a issecured to the lever 39a and extending to an anchor 42b located toextend the spring 42a across or adjacent the axis of the pivot 3% whenthe lever 39a and cross head '39 are in their lower positions. Thus thesprings 22a will have little eiect on the cross head 39' when it is downbut when it is moved up `the spring `42a will strongly urge the lowerarm of the lever 39a against the cross head 39 to hold it up with thepins 40 in the form. Thus the lever 39a and spring 42a will ser-ve as adetent opposing movement of ythe pins 40 `from their position extendinginto the form.

Qpposite the pivots 45 and 49 there :is secured to the lever 46 at 54 apull rod 55 extending up through an arm 56 on the slide 15. A nut 57 isengaged with the rod 55 above the arm 561130 limit `the upper movementof the arm 56 with respect to the rod 55. When the pins 40 are up andthe parts 441, 47 and 51 in their positions shown dotted in FIG. 3, thearm 56 will engage beneath the nut 57 and will move the rod 55 upwardlyto the solid line position. This will also move the levers 47 and 51,the arm 44 and the pins' 4) to their solid line positions, therebyretracting the pins rfrom the mold to a position below :the table 7 sothat the table 7 may be moved for ready removal and replacement of thelled form 8.

The dowel holes in the upper end of theV conduit are provided by theVdowel hole forming pins '58'. These pins are carried on a cross head 59suspended by suspension rods 5u from the slide 15. These rods passthrough'the slide and have nuts 61 `on `their upper ends limiting theupward movement of the slide 15 with respect thereto.

These rods are secured to the cross head 59' by means of nuts 62. Whenthe slide 15 is in its Aupper position the cross head 59 will besuspended as shown in FIG. l and the pins `58 will be held with theirupperends in or above the upper surface of the table 25 and above theupper end of the `form 8. Thus ali dowel hole formers are withdrawnbefore the form ends are removed and not afterward.

T-he cross head 59` is provided with laterally extending ears orextensions 63 adapted when the cross head is lowered to engage on top ofthe support elements, 6 carried by the frame so as to suspend the crosshead in its lower position as illustrated in FIG. 4. When in thisposition it will be seen that the pins 58 extend downwardly through theopenings 28 in the table 25 and into the interior of the form 8 so as toprovide dowel holes in a conduit formed in such form when the pins areAthus in place. The rods 60, being slidable through the slide 15, merelystop moving downwardly when the projections 63 engage the support y6 toarrest movement of the cross head 59 and the pins `58, but the slide |1Sis permitted to continue its downward movement thereafter.

4In operation, the form is put in place while the various par-ts of themachine occupy the positions illustrated in FIG. l except that, ofcourse, the form at this stage is empty but has the bottom plate 10 inplace therein. The hydraulic cylinder mechanism comprising the cylinders31 and the .rods 32 is then operated to start the slide 15 downwardly.This downward movement carries the packer heads 19 downwardly throughthe interior of the form until they engage the openings in the bottomwall 10 and the support table 7 as illustrated in FIG. 4.

As the slide starts down the cross head 59 and the pins 58 start downwith it until the extension 63 engage on top of the supports 6 and stopthis downward movement. The point at which this downward movement stopsis illustrated in FIG. 4 with the lower ends of pins 58 extending intothe form 8 far enough to provide the necessary ydepth of dowel holes inthe upper end of the form. Thereafter downward movement of the slidedoes not change the position of the cross head 59* or the pins 58.

The initial ydownward movement of the slide 15 likewise producesdownward movement of the loading table 25 until this table rests on topof the form 8, whereupon its downward movement is arrested. It is note-dthat this downward movement is arrested after only a short distance andthat `since the rods 24 are slidable in the slide l5, the slide 1'5 maycontinue its downward movement thereafter. The downward movement of thecross head 59 is not arrested by engagement of lthe parts 63 with thesupports v6 until substantially later than the arrest of the downwardmovement of the table 25, so that the pins S8 coninue their downwardmovement until they project through the openings 28 and into the form 8.

During the same downward movement of the slide 15 the lower pins 40remain in their lowermost position until this slide reaches a point nearthe lower end of its travel at which position the slide 15 engages thelever 51 and as the downward movement of the slide 15 continues thelever 51 is moved from a solid line position to its dotted lineposition, this latter position being reached just as the lowermost pointof fthe travel of the slide I15 is attained. As hereinbefore described,this movement of the lever 51 causes the upward movement of the arm 44and the pins 4.0l until these pins project into the form a sufficientdistance to provide the dowel pin holes 43 in the lower end of a conduitformed in this form.

The packer heads are then rotated and the feeder mechanism 30 operatedto feed cement mix into the hopper formed by the flange 29' and -thismix is vpushed in through the openings in the table 25 through which thepacker heads moved on their downward movement. As this material falls onand around the packer heads it is packed in place as shown in the lowerportion of FIG. 4 and as soon as .the lower end of the form becomesfully packed with cement mix, the slide 15 is started on a relativelyslow upward movement while rotation of the packer heads 1 9'y continuesand the feeding of the cement mix v into the ferm also continues. Duringthis upward movement the pins 40 remain in their position projectinginto the lower end of the iorm and the pins 58 remain in their positionprojecting into the upper end of the form until the point is reached atwhich the arm 56 engages the nut 57 and the upper surface ofthe slide 15engages the nuts 61. It is noted that this will Yoccur before the table25 which forms ythe top of the mold 8 is lifted olf the top of the mold.Thereupon `further upward movement `of the slide 15 acts throughk therods 55, the leve-i147, the rods and the arm 44 -to lower the pins 40.to a position with their upper ends below the table 7.

Thus it will -be seen that the pins -40 and 58. will be extracted fromthe conduit formed in the mold in the form 8 while the end Walls of thisform are still in position thereby preventing any breaking away of anyportion of the unset concrete in the mold by the removal of these pins.It will also be seen by observing FIG. l that the pins will be removedsubstantially as the slinger portions at the upper ends of ythe packe-rheads emerge from the upper end of the form 8 so that the holes formedby the pins '5S will not be closed by action of the slingers after theremoval yof the pins 5S and the only action upon the interior of theducts through the conduit after the removal of the pins 58 will be theaction of the troweling sections 19 which do not tend to further packthe cement mix but merely Ito smooth the walls of the ducts in theconduit. After complete removal of the packer heads 19 has taken placethe suspension rods 24 will come into play ydue to the engagement of theupper surface of the slide 15 with the nuts 26, and thereupon the table1)J5 which forms the upper end of the mold will be removed from theupper end of the mold. The parts will then be in position so that thesupport table 7 may be rotated on its pivot 9* to a point where the-mold 8 is readily accessible for removal from the machine and anothermold may be putin place and the process repeated.

It will he seen from the `foregoing that a means has been providedwherelby dowel pin holes may be formed in the opposite ends of a conduitin the course of forming `the conduit, that the pins that form suchholes may then be removed without any possibility of damage to theconduit thus [formed and without any :arduous labor or care necessary inthe process.

From the foregoing it will be seen that this invention is one welladapted to attain all of the ends and objects hereinabove set forth,.together with other advantages which are obvious and which are inherentto the structure.

It will Ibe understood that certain features and subcombinations are ofutility and may tbe lemployed without reference to other features andsubcombinations. This is contemplated by and lis within the scope of theclaims.

As many possible embodiments may he made of the invention withoutdeparting from the scope thereof, it is .to be understood that allmatter herein set forth is to he interpretedv as illustrative and not ina limiting sense. l The invention having been described, what is claimed1s:

1. In :a conduit [forming machine of the type having a frame, a dormsupport thereon, a form on said support having endswith aligned openingstherein in positions registering with the ends of a duct to be formed ina conduit in said form, a packer head, a packer head supporting Fanddriving shaft carrying said head, and means on the frame and endwisefrom said form for rotatably and longitudinally slidably mounting saidshaft Ion said frame in vaxial alignment with said openings in oneendwise direction from said dorm, said slidable mounting means providinglimits for sliding movement of said shaft great enough to permitmovement of said head through said `form from one end to the other andout of said 7 form through the opening in one end of said form, anddriving means including means for rotating said shaft and head and meansfor simultaneously sliding said shaft to move said head longitudinallythrough and out of said form, the improvement which comprises opposeddiowel hole :forming pins, guide means on the frame spaced from andopposed to the opposite ends of said form'and siidably supporting saidpins with, their axes parallel rISO the `axis of said shaft for axialsliding movement into and from said formv through the opposite endsthereof respectively between positions extending into said [form throughsaid respective ends and positions outside and clear of said form, meansinterconnecting said opposed pins for moving one in `one axial directionupon movement of the other in the opposite direction, and a lost motioncontrol means interconnecting one of said pins and said shaft for movingsaid pins to their positions extending in-to said iform upon movement ofsaid shaft passing said ihead through said Iform to the end thereofopposite the mounting of said shaft, and ttor moving said ReferencesCited in the le of this patent UNITED STATES PATENTS 1,428,044 MartinSept. 5, 1922 1,937,350 La Due Nov. 28, 1933 2,530,687 Dixon Nov. 21,1950 2,875,499 Ross Mar. 3, 1959 FOREIGN PATENTS 2,085/26 Australia Mar.18, 1927 i i i

1. IN A CONDUIT FORMING MACHINE OF THE TYPE HAVING A FRAME, A FORMSUPPORT THEREON, A FORM ON SAID SUPPORT HAVING ENDS WITH ALIGNEDOPENINGS THEREIN IN POSITIONS REGISTERING WITH THE ENDS OF A DUCT TO BEFORMED IN A CONDUIT IN SAID FORM, A PACKER HEAD, A PACKER HEADSUPPORTING SAID DRIVING SHAFT CARRYING SAID HEAD, AND MEANS ON THE FRAMEAND ENDWISE FROM SAID FORM FOR ROTATABLY AND LONGITUDINALLY SLIDABLYMOUNTED SAID SHAFT ON SAID FRAME IN AXIAL ALIGNMENT WITH SAID OPENINGSIN ONE ENDWISE DIRECTION FROM SAID FORM, SAID SLIDABLE MOUNTING MEANSPROVIDING LIMITS FOR SLIDING MOVEMENT OF SAID SHAFT GREAT ENOUGH TOPERMIT MOVEMENT OF SAID HEAD THROUGH SAID FORM FROM ONE END TO THE OTHERAND OUT OF SAID FORM THROUGH THE OPENING IN ONE END OF SAID FORM, ANDDRIVING MEANS INCLUDING MEANS FOR ROTATING SAID SHAFT AND HEAD AND MEANSFOR SIMULTANEOUSLY SLIDING SAID SHAFT TO MOVE SAID HEAD LONGITUDINALLYTHROUGH AND OUT OF SAID FORM, THE IMPROVEMENT WHICH COMPRISES OPPOSEDDOWEL HOLE FORMING PINS, GUIDE MEANS ON THE FRAME SPACED FROM ANDOPPOSED TO THE OPPOSITE ENDS OF SAID FORM AND SLIDABLY SUPPORTING SAIDPINS WITH THEIR AXES PARALLEL TO THE AXIS OF SAID SHAFT FOR AXIALMOVEMENT INTO AND FROM SAID FORM THROUGH THE OPPOSITE ENDS THEREOFRESPECTIVELY BETWEEN POSITIONS EXTENDING INTO SAID FORM THROUGH SAIDRESPECTIVE ENDS AND POSITIONS OUTSIDE AND CLEAR OF SAID FORM, MEANSINTERCONNECTING SAID OPPOSED PINS FOR MOVING ONE IN ONE AXIAL DIRECTIONUPON MOVEMENT OF THE OTHER IN THE OPPOSITE DIRECTION, AND A LOST